Vibratory arc device



Oct. 5, 1965 M. cLEvEYT-r, JR 3,210,586

VIBRATORY ARC DEVICE Filed Aug. 25, 1960 MERTON L. CLEVETT I INVENTOR. H BY /fnf/@M/ ATTORNEYS United States Patent Ofce 3,210,586 Patented oci. 5, ieee 3,210,586 VIBRATORY ARC DEVlCE Merton Lloyd Clevett, Jr., Natick, Mass., assignor to Aveo Corporation, Cincinnati, Ohio, a corporation of Delaware Filed Aug. 25, 1960, Ser. No. 51,867 19 Claims. (Cl. 313-146) This invention generally relates to arc devices and in particular to plasma generators in which a fluid is passed through yan electric arc and emerges from the arc as a plasma effluent. In this discussion a plasma is defined as an electrically neutral effluent of ions and electrons.

Under normal room ambient conditions of temperature and pressure, a fluid disposed in an electric field is nonconductive; it will not conduct a substantial Vamount of current. To make the fluid conductive7 it is necessary to heat a fluid until it is at least partially ionized, `at which point the ionized fluid becomes a medium for conducting current. The conduction point is determined by the temperature of the fluid and the magnitude of the electric field. To a point, conduction, once started, is a regenerative action. The current flowing in the fluid further heats the fluid thus increasing the ionization of the fluid until an equilibrium condition is achieved.

Generally, in arc devices such as welding tools and plasma generators, it is necessary to provide means for initiating `an arc `discharge through a normally nonconductive fluid lying between a pair of electrodes. One prior art method used is to bring the -arc electrodes, across which there is an electrical potential difference, into contact and then slowly -breaking the contact. The heat generated by the short circuit current coupled with the high electric field produced immediately after the electrodes are separated is of sufficient magnitude to ionize the fluid, initiating an arc discharge.

Where it is not feasible to perform the aforementioned procedure because the electrodes must remain in a fixed position, the prior art also shows two other ways of initiating an arc discharge between a pair of electrodes. The first is to connect a fine wire, usually tungsten, between the electrodes before applying electric power. The Wire is raised to an incandescent temperature by an electric current. The heat generated in the wire heats the surrounding fluid causing it to ionize, initiating an arc discharge. The starting wires are destroyed in this procedure and must be replaced before each operation of the arc device. In many cases, because of the structure of the arc device, it is inconvenient to insert a starting wire. This is particularly so in small plasma generators where the opening in the nozzle electrode of the plasma generator is extremely small, in the order of 1A inch diameter. The wires are generally inserted by hand.

A second starting procedure is to superimpose on the primary arc power supply-t-hat which is to maintain the arc once it is formed-an extremely high frequency, high voltage, signal. This type of signal causes a discharge current to flow lbetween the arc electrodes even under conditions where a fluid positioned between the electrodes is nonconductive to the primary arc power. The high frequency signal causes the flow of particles in the column of fluid situated Ibetween the fluids to reverse vat an eX- tremely high rate in synchronism with the reversal of polarity in the applied high frequency signal. The rapid oscillations of these particles causes them to heat up. Finally, a temperature is reached at which the column of fluid becomes ionized, and thus conductive to the arc maintaining power, and a high energy arc discharge is developed. l

The principal disadvantage of the high frequency starting mechanism is the high initial cost of the high frequency generating equipment. It will also be noted that this equipment is normally used only for starting arcs. When it has performed its function, it is disconnected.

All of the starting procedures just discussed cannot be used Where the power for maintaining the high intensity arc is derived from an A.C. power supply, such as the normal power distribution means. In a normal A.C. pattern, the voltage passes through zero twice during each cycle of operation. Each time the voltage passes through zero the electric field between the arc electrodes which is maintaining the arc disappears and the arc is extinguished. Normally in plasma devices, and in particular in the plasma generator where a continuous stream of fluid is passing between the electrodes, the ionized column between the electrodes is blown out and replaced by a nonconductive column. Since the alternating voltage passes through zero times a second, in conventional 60 cycle power distribution means, it is obviously impossible to use the manual starting procedure and the wire starting procedure. The use of the high frequency generator is impractical since the generator would have tobe continuously applied to the electrodes and accordingly must be capable of operating under widely fluctuating impedance conditions, such las the lower resistance path developed when the arc is ignited and the high resistance path developed when the arc is extinguished. To make a high frequency generator immune to these wide impedance fluctuations would greatly add to the already formidable cost of these equipments.

lt is an object of the invention to provide an arc device which -avoids the limitations and disadvantages of such prior art devices.

It is another object of the invention to provide a low cost self-starting arc device and, in particular, a selfstarting plasma generator which can be manufactured at an extremely low cost.

It is still another object of the invention to provide an arc device and in particular a plasma generator which is operated directly from a typical electrical distribution system, e.g. 11%20 single-phase or three-phase household distribution.

It is yet another `object of the invention to provide an' arc device and in particular a plasma generator in which one electrode can be rapidly moved toward and away from a second electrode for starting and maintaining an arc.

It is still another object of the invention to provide an arc device and in particular a plasma generator including a nozzle electrode and a central electrode, wherein the central electrode is vibrated toward and away from the nozzle electrode by mechanical means or by a fluid passing over the central electrode.

It is yet another object of the invention to provide an arc device and in particular a plasma generator comprising a nozzle electrode and a central electrode wherein the central electrode is positioned symmetrically with respect to the nozzle electrode by fluid passing thereover.

Other objects of the invention are to provide a plasma device and in particular a plasma generator which:

(l) includes means for rapidly separating the nozzle electrode from an assembled device;

(2) includes means for moving an electrode into the arc region to compensate for the consumption and degradation of the electrode by the arc;

(3) includes control means for adjusting the electrode feed rate; and

(4) is a low cost spray coating device and in particular a spray coating device which operates directly from an electrical distribution means without ancillary starting equipment.

In accordance with the invention an arc device comprises a first electrode shaped in the form of a nozzle.

A second electrode adapted to move toward and away from the first electrode, tending to or making and breaking contact with the first electrode, is positioned Within the nozzle opening. The arc device also includes means for passing a uid into contact with the second electrode for moving the second electrode toward and away from the rst electrode very rapidly whereby an arc discharge is produced. The uid eventually passes between the rst and second electrode and out of the nozzle opening as a plasma efuent.

The aforementioned arc device may also include means whereby the nozzle electrode may be quickly and easily `separated from the arc device to simplify replacing the electrodes and means whereby the central electrode can be fed toward the nozzle electrode thus compensating for the loss of material from the central electrode due to its consumption and degradation by the arc. Control means is provided for the feed mechanism whereby the rate of feed is adjusted.

The novel features that are considered characteristic of the invention are set forth in the appended claims; the invention itself, however, both as to its organization and method `of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in conjunction with the accompanying drawings, in which:

lFIGURE l is a cross sectional diagram of a plasma generator which employs the principles of the present invention;

FIGURE 2 is a cross sectional diagram taken along line 2 2 in FIGURE 1;

FIGURE 3 is a cross sectional diagram taken along line 3-3 in FIGURE 1;

FIGURE 4 is a cross sectional diagram taken along lines 4-4 in FIGURE 1;

FIGURE 5 is a cross sectional diagram of the nozzle end of the FIGURE 1 plasma generator showing an alternate design of quick release mechanism for securing the nozzle; and

FIGURE 6 shows an alternate construction of the central electrode support structure.

Referring to FIGURE 1 of the drawings there is depicted a cross sectional diagram of a plasma generator 10. The plasma generator 10 includes a tubular housing 11 having a handle 12 depending from one end thereof. The housing 11 includes an open ended uid chamber 13 and an open ended arc chamber 14 separated by a partition 16. The partition 16 is secured to the housing 11 in any suitable means. The set screw 17 threaded through the housing into the partition, as illustrated, is but one example. The partition 16 includes a centrally disposed (concentric with an axis 18 of the housing 11) longitudinal passage 19. An eccentric passage 21, which is radially spaced from the passage 19 is also delined through the partition 16. The passages 19 and 21 are lined with metallic sleeves 20 and 15 respectively.

The open end of the uid chamber 13 is closed with a cap 22 formed from a nonconductive material, preferably a plastic material. The cap 22 includes a centrally disposed passage 23 and an eccentric passage 24, one end of which opens into a counterbore 26.

The open end of the arc chamber 14 is covered by a nozzle electrode 27 formed from any electrically conductive material that is capable of operating at high temperatures. Graphite is preferred because it is relatively inexpensive and can be easily formed, although for some purposes copper and tungsten may be used. The nozzle 27 also includes a centrally disposed passage 28. Preferably, the internal end 29 of passage 28 flares outwardly. The flare creates a form of venturi nozzle, the precise shape of which controls the exit velocity and pressure of a fluid owing in passage 28. The nozzle electrode 27 also includes a third eccentric passage 31 one end of which opens into a counterbore 32. The eccentric passages 21, 24 and 31 respectively are coaxial.

The nozzle electrode 27 and the cap 22 are secured to the housing 11 by an electrically conductive bolt 33 passing through the eccentric passages 21, 24 and 31. The bolt terminates at each end in a threaded portion which extends into the counterbores 26 and 32 respectively. Nuts 34 and 36, shown threaded on the ends of bolt 33 secure the nozzle electrode 27 and the cap 22 to the housing 11 and effectively seal the fluid charnber 13 and the arc chamber14.

A centrally disposed electrically conductive electrode support 37 is also included within the housing 11. The electrode support 37 is formed from a tube, or sleeve, and passes 'through the first central aperture 19 and the second central aperture 23. The tubular electrode support 37 terminates in an exterior end 38 extending from which is a knob 39. The other end of the electrode support 37 extends into the arc chamber 14.

The electrode support includes a transverse hole 42 defined within its Walls. See FIGURE 2. The walls of electrode support 37 define a passage 35 which with transverse hole 42 provide the only open access between chambers 13 and 14.

Extending from the electrode support 37 in the arc chamber is an electrically conductive helical spring 43 which is secured to the electrode support 37 by means of a collar 44. See FIGURE 3. A collar 46 (FIGURES l and 4) is used to join the helical spring to a pencilshaped central electrode 47 which extends from the helical spring into the first central passage 28 in the nozzle electrode 27. It is significant to note that while the central electrode is substantially co-axial with the housing axis 18, it is not a requirement, as will be explained hereinafter.

Since plasma generators typically operate with large magnitudes of current in the order of or 1,000 amperes7 a good conductor of electricity 48 is fastened to the collars 44 and 46 so that the spring 43, which may not be a good electrical conductor, will not be required to ycarry the full power needed to maintain a high intensity arc.

The electrode support 37 is slidably mounted within the sleeve 20 and passage 23 respectively. Thus, the position of the central electrode 47 with respect to the nozzle electrode 27 can be adjusted axially by moving the electrode support 37 toward or away from the nozzle electrode Means are provided for locking the electr-ode support in a xed position or for providing an adjustable frictional force on the surface of the electrode support 37. This means, hereinafter referred to as the control means 49 comprises a knob 51 from which a threaded stem 52 depends. The threaded stern 52 is inserted into a complementary threaded passage 53 included in the cap 22 as shown in FIGURE 1.

Finally, the plasma generator 10 comprises means for supplying electrical power to the electrode, and means yfor supplying a fluid to the uid chamber 13. Electrical power is provided to the plasma generator 10 by passing a pair of electrical conductors 53 and 54 from an electrical power supply means (not shown) through a conduit 56 supplied in the handle 12. One end of the conduit 56 opens into the fluid chamber 13 and the conductors 53 and 54 are connected to the sleeves 20 and 1S respectively.

Fluid is coupled from a supply means (not shown) to a conduit 57 included in the handle 12 and is coupled to the fluid chamber 13 as indicated in FIGURE 1. Ineluded in addition to the conduit 57 is a valve mechanism 5S for adjusting the rate of fluid flow to the uid chamber 13.

The design and construction of the uid valve is not critical. The valve 58 is merely illustrative of a simple and inexpensive mechanism. Under the inuence of the fluid the ball S9 is pressed against `the mouth 61 `of a conduit 62 thus cutting off the ow of fluid to the Huid charnber 13. A trigger 63 is provided for moving the ball laterally for opening the mouth 6l for the passage of fluid into conduit 62 and then to the fluid chamber 13. The magnitude of uid flowing in the conduit is a function of the amount of lateral displacement of the ball 59. The trigger 63 passes through a resilient member 64 preferably a rubber pad which provides the necessary spring action for moving the trigger to its normally inoperative position.

Operation of the FIG URE 1 plasma generator At the outset it is presumed that electrical power is coupled through conductors 53 and 54 and through the electrode support 37 and bolt 33 to the central electrode 47 and the nozzle electrode 27 respectively. As will be obvious from the discussion to follow, this electrical power may be derived from a unidirectional, or D.C. source (not shown), or an alternating or A.C. source (not shown). Since A.C. poses a more serious problem to the operation of plasma generators, it will be assumed that A.C. power is applied to the electrodes 47 and 27. It is clear from the FIGURE l construction that the position of the central electrode 47 relative to the nozzle 27 is not rigorously controlled and accordingly, the central electrode may be touching nozzle electrode 27 or spaced therefrom. It is immaterial which initial position exists. However, for purposes of this discussion the central electrode is assumed to be spaced from the nozzle electrode 27. The final assumption is that the conduit 57 is coupled to a fluid supply means, not shown. The fluid may be water, steam, an inert gas, or air. In addition, where it is desired to use the plasma generator as a spraying device for coating surfaces, for example, the fluid spray means may comprise a mixture of air and particles of the coating material. Initially, the fluid is prevented from passing from conduit 57 to conduit 62 and subsequently to the fluid cham-ber 13 by the valve Sti.

To ignite the arc the trigger 63 is fully depressed thus moving the ball 59 to its most remote position. Thus, initially the fluid entering the fluid chamber 13 enters under the full pressure available from the fiuid supply means. Since one end of the electrode support 37 is blocked by the knob 39 the uid must pass to the arc chamber 14. From the fluid chamber 13 the fluid passes through the apertures 42 and passages 35 in the electrode support 37 into arc chamber 14. The fluid leaves the electrode support 37 as a high velocity effluent and i-mpinges upon the end of the central electrode 47 that is secured in the collar 46. The force of the fluid against the central electrode 47 causes the electrode to start vibrating since it is connected to the electrode support 37 by the spring 43. During the course of vibration the central electrode 47 moves toward and away from nozzle electrode 27 very rapidly.

The magnitude of lateral movement 47 toward the nozzle electrode 27 can be controlled by the amount of fluid, and the fluid pressure thereof, permitted to pass through the arc dev-ice. Once the arc is formed the flow of fluid may be decreased through valve 58.

It has been brietiy mentioned before that ionization of a fluid is to a large extent determined by the temperature of the fluid and the electric field intensity. It is proposed to dwell on the matter of the electric field intensity. As shown in Equation (l),

The electric field intensity E is proportional to voltage V, in this case the potential difference between the arc electrodes and inversely proportional to the distance d separating the electrodes; R is a constant. Thus, as one electrode moves toward the other the electric field intensity increases rapidly and approaches infinity just before the electrodes make contact. Under certain conditions, particularly after the arc has been in operation for sometime and the electrodes are extremely hot, an arc can be reignited without the electrodes coming into contact. The proper conditions of temperature and electric field intensity will arise when the movable electrode is adjacent to the fixed electrode and spaced therefrom.

Experiments with devices of the type discussed herein have shown that contact between the electrodes is usually necessary where an arc is to be developed with an equipment that had been inactive for a considerable length of time. However, after the short interruptions in the operation or during the course of a run, using A.C power, where the voltage supplied to the electrodes drops to zero one hundred and twenty times per second, contact between the electrodes is not necessary to reignite the arc.

The vibration motion is entirely random and it is conceivable that the electrodes will make contact at a time when there is zero voltage potential between them. This is considered a wasted motion. However, experience has shown that the frequency of vibration is suflciently high so that a seemingly continuous arc exists between the central electrode 47 and the nozzle electrode 27. Under close scrutiny this seemingly continuous arc is actualy being interrupted many times. The gas flowing between the electrodes is heated by the arc and leaves the plasma generator as a plasma effluent 66.

It has also been observed that the passage of uid through the electrode support 37 urges, or tends to move the electrode support 37 axially forward, tending to move the central electrode 47 further into the nozzle electrode 27. Where there is no restraining force on the electrode support 37 the force generated by the fluid will cause these two electrodes to come into permanent contact thus short circuiting the electrical power supply. Accordingly, it is another feature of this invention to provide a control means whereby the aforementioned tendency for the electrode support to move can be either prevented or controlled, preferably the latter since the tip of the central electrode 47 will be consumed with time. The control means as described heretofore comprises a knob 51 from which a threaded stem 52 depends. The threaded stem 52 is inserted in a complementary hole 53 to permit the tip of the stem to make contact with the outer surface of the electrode support 37. The magnitude of friction between the tip of the stem 52 and the electrode support 37 may be adjusted with respect to the force generated by the fluid to provide a predetermined rate of movement of the electrode support 37. This facility for compensating for further consumption of the central electrode 47 makes it possible to extend the time to which the plasma generator may be operated Without interruption.

In the absence of vibration, the fluid passing through the arc chamber 14 around the central electrode 47 through the ared portion 29 of the nozzle electrode 27 tends to center the central electrode 47 symmetrically within the aperture 28 in nozzle electrode 27. This selfcentering feature is believed to be responsible for the uniform consumption of the outer surface of the central electrode. Since the normal tendency of the electrode is to remain centered, and since the vibrating action is completely random, instantaneous contact will be made between the central electrode and the nozzle electrode 27 throughout the surface of the former as time passes. In other Words, the random nature of the electrode movement causes arcing to move over the surface of the electrode; unlform wear results.

Description and operation of the FIGURE 5 modification In FIGURE 5 there is depicted the front portion of the FIGURE 1 plasma generator which includes an alternative construction for mounting the central electrode 47 and vibrating it. It will be noted that the central electrode 47 is mounted to an electrical support 37 in a bayonet like fashion by a resilient leaf 71. It will also be noted that '7 the end of the electrode support 37 shown is closed and includes a rivet means 73 which secures the leaf spring 71 to the electrode support 37. The electrode support 37 includes a longitudinally extending passage 74 through which fluid is supplied. The electrode support 37' also includes internally a mass or plunger 76 which is held against the opening in passage 74 by a spring 77 acting Vagainst the closed end 72. A pair of transverse holes 7 8 are constructed through the walls of the electrode support 37.

As the fluid enters passage 74 under pressure it forces the mass 76 forward and compresses spring 77. As the mass passes the transverse apertures 78 the iiuid flows out of the aperture '78 into the arc chamber 14 and then through the nozzle opening 28 and out of the plasma generator. The illustrated device is designed to provide a pulsating flow of fluid which creates su'iiicient turbulence within the arc 14 to initiate a vibrating movement of the central electrode 47. The leaf spring 71 illustrates an alternative resilient mounting method which could be used where the helical spring shown in FIGURE 1 could not be applied. It has an obvious limitation in that the central electrode 47 will vibrate in the random fashion but not symmetrically as discussed heretofore. The lack of symmetry, however, ampliiies the lateral movement of electrode support 37 caused by the pulsating flow of fluid.

Another means for vibrating the central electrode cornprises securing an electromagnetic vibrator 80 to the housing 11. Since any of the well-known forms may be used a dotted block representation is shown in FIGURE 5. The vibrator 80 may be used as the principal vibrating means or it may be used to supplement the fluid.

Description and operation f the FIGURE' 6 nozzle construction Arc devices in plasma generators in particular generate extremely high temperatures. They are preferred over other devices because they can either equal or surpass other devices in temperature. As a result of these high temperature environments, the electrodes are subject to severe deterioration and degradation. This is particularly serious in devices such as that illustrated since no effort is shown for cooling these electrodes. Accordingly, it is particularly advisable to provide a simple means for replacing electrodes when this becomes necessary. In FIGURE 6 there is shown a construction utilizing a spring detent mechanism 81 supported in the housing 11 and extending into complementary recesses 82 formed in in the nozzle electrode 21. Thus, to replace the nozzle electrode or to replace the central electrode it is merely necessary to pull the nozzle electrode 27 with sufcient force to overcome the restraining force of the detent mechanism S1 and make the necessary replacement. It will be noted that the bolt 33 is merely inserted, as a force lit into the off set aperture 31. The contact between the bolt 33 and the walls for the aperture 31 are suicient to create a low resistance path for the current ilowing from the nozzle electrode to the bolt 33. A similar construction may be used in connection with the cap 22.

A plasma device that can be constructed and operated in a simple and facile manner, at an extremely low manufacturing cost, $100.00 or less, is the primary design objective of the present invention. It will be readily appreciated that the plasma generator 10, FIGURE l, is a self-contained unit which can be made fully operative by merely supplying electrical power from a conventional utility outlet and fluid, from Widely used air supply means. There is no need for ancillary starting equipment. Although the plasma generator 10 can be used with a D.C. power supply, it has the unique ability of being fully operable with A.C. power. In connection with the principal objective, a simple facility for replacing electrodes is provided. It will be noted that the feed mechanism` for axially moving the central electrode Se toward the nozzle electrode requires only a single, simple and inexpensive, additional part.

The various features and advantages of the invention are thought to be clear from the foregoing description. Various other features and advantages not specifically enumerated will undoubtedly occur to those versed in the art, as likewise will many variations and modifications of the preferred embodiment illustrated, all of which may be achieved without departing from the spirit and scope of the invention as defined by the following claims.

I claim:

1. An arc device comprising: a first electrode; a second electrode adapted to vibrate toward and away from said first electrode for making and breaking contact with said irst electrode; means for coupling said rst and second electrode to an electrical power supply means; and means for randomly impacting a iluid stream against said second electrode for vibrating said second electrode.

2. An arc device comprising: a rst electrode; a second electrode adapted to vibrate toward and away from said iirst electrode for making and breaking contact with said rst electrode; means for coupling said rst and second electrode to an electrical power supply means; and iluid means for randomly acting directly on said second electrode causing it to vibrate.

3. An arc device comprising: a first electrode; a second electrode resiliently mounted to vibrate toward and away from said rst electrode for making and breaking contact with said first electrode; means for coupling said first and second electrode to an electrical power supply means; and means for randomly passing a fluid stream into contact with said second electrode for vibrating said second electrode.

4. An arc device comprising: a first electrode including a passage; a second electrode positioned co-axially with and adjacent to the passage and resiliently mounted to vibrate laterally toward and away from said first electrode for making and breaking contact with said first electrode; uid means for imparting a fluid stream to said second electrode for laterally vibrating said second electrode; and means for coupling said first and second electrode to an electrical power supply means.

5. An .arc device comprising: a housing having an open end; a nozzle electrode disposed in the open end having a passage; an electrode assembly mounted co-axially with respect to the passage including a second electrode which is vibratable laterally, said electrode assembly being movable axially; fluid means for imparting a iluid stream to the electrode assembly for vibrating the second electrode and for urging the electrode assembly axially toward the nozzle electrode; means for preventing or restraining the axial movement of said electrode assembly; and means for coupling said nozzle and second electrodes to an electric power supply means.

6. An arc device as described in claim 4 in which said means for restraining the axial movement of said electrode assembly comprises means for applying an adjustable frictional force to said electrode assembly.

7. An arc device as described in claim 5 in which said electrode assembly includes an electrode support member mounted to said housing and movable axially with respect thereto, which is connected to the central electrode by a spring.

8. An arc device comprising: a housing having an opening; a iirst electrode covering the opening and including a central passage; an electrode lsupport member mounted to said housing; a second electrode partially disposed within the central passage and resiliently secured to said electrode support for lateral movement toward and away from said rst electrode; means for inducing said second electrode to vibrate toward and away from said iirst electrode; and means for supplying electrical power to Said first and second electrodes.

9. An arc device as described in claim 8 in which the electrode support, the central passage and said second electrode are co-axial and said electrode support is movfable axially toward said first electrode.

10. An arc device comprising: a housing having an opening; a first electrode covering the opening including a central passage; an electrode support means slidably mounted to said housing for moving toward said first electrode; a second electrode resiliently mounted to said electrode support for movement toward and away from said first electrode independently of the movement of said electrode support; means for inducing said second electrode to move toward and away from said first electrode and for urging said electrode support toward said first electrode; means for supplying electric power to said electrodes; and means for controlling the rate of movement of said electrode support means.

11. An arc device as described in claim in which said last mentioned control means comprises means for imparting an adjustable frictional restraining force on said electrode support means.

12. An arc device comprising: a housing having a fluid chamber and an arc chamber, the latter having an open end; a first electrode covering the open end having a fluid exit passage defined therein; means for supplying fluid to the fluid chamber; a second electrode resiliently connected to said fluid conducting means in the fluid stream, said second electrode being disposed adjacent to said first electrode and movable toward and away from said first electrode directly by said fluid; and means for supplying electric power to said electrodes.

13. An arc plasma device comprising: a tubular hous ing including an open ended fluid chamber and an open ended arc chamber separated by a partition having a first centrally disposed longitudinal passage; a cap disposed within the open end of the fluid chamber covering the fluid chamber including a second centrally disposed lon gitudinal passage; a nozzle electrode disposed within the open end of the arc chamber covering it including a third centrally disposed longitudinal passage; an electrically conductive tubular electrode support slidably positioned within the first and second centrally disposed passages terminating in an exterior end outside of the housing and a second end lying within the arc chamber, said exterior end including knob means for sliding the tubular electrode support within the aforementioned centrally disposed passages; helical spring means secured to the second end of the electrode support and extending substantially co-axially therefrom; a pencil-shaped electrode secured to and extending from the helical spring terminating in a marginal end disposed within the third centrally disposed longitudinal passage of the nozzle; means in fluid communication with the fluid chamber and in cluding valve means for adjusting the ilow of lluid to the lluid chamber; means for supplying electrical power to said electrodes; and friction means for applying a frictional force to the tubular electrode support for controlling the translation thereof.

14. A n arc device comprising: a first electrode; a seond electrode adapted to vibrate toward and away from said first electrode; means for coupling said first and second electrode to an electrical power supply means; and means for passing a pulsating fluid stream into contact with said second electrode for randomly inducing vibration thereof.

1S. An arc device comprising: a first electrode; means for supplying fluid under pressure; valve means coupled to the fluid supply means responsive to pressure thereof for developing a pulsating flow of fluid; second electrode means acted on by said fluid adapted to to move toward and away from said first electrode in response to the pulsating llow 0f fluid; and means for coupling said first and second electrode to an electrical power supply means.

16. An arc device comprising: a housing having a fluid chamber and an arc chamber, the latter having an open end; a first electrode covering an open end having a fluid exit passage defined therein; means for supplying fluid to the fluid chamber; an electrode support means disposed within the fluid and arc chambers, said electrode support means including conduit means having an input means in the fluid chamber and an outlet means in the arm chamber; a second electrode resiliently connected to said electrode support means, said second electrode being adjacent to said fluid outlet means and movable toward and away from said first electrode directly by said fluid; valve means connected to said electrode support means normally closing the outlet means, said valve means being acted on by the fluid for repeatedly opening the output means; and means for supplying electrical power to said electrodes.

17. An arc device as described in claim 16 in which said valve means comprises a slidable plunger mounted within the conduit and normally covering the outlet means, said plunger being resiliently urged in opposition to the desired direction of fluid flow.

18. An arc device as described in claim 16 which includes in addition a quick release mechanism interconnecting the housing and said first electrode for detachability, securing said first electrode to said housing.

19. An arc device as described in claim 18 in which said release mechanism comprises a spring detent mechanism secured to the housing and a complementary recess defined in said first electrode.

References Cited by the Examiner UNITED STATES PATENTS 2,490,302 12/49 Holfelder 219-69 2,844,751 7/58 Prescott S13- 146 X 2,850,662 9/58 Gilruth S13-231.5 2,855,473 10/58 Rabinow 200-19 2,892,118 6/59 Gretener 313-149 GEORGE N. WESTBY, Primary Examiner. RALPH G. NILSON, ARTHUR GAUSS, Examiners. 

1. AN ARC DEVICE COMPRISING: A FIRST ELECTRODE; A SECOND ELECTRODE ADAPTED TO VIBRATE TOWARD AND AWAY FROM SAID FIRST ELECTRODE FOR MAKING AND BREAKING CONTACT WITH SAID FIRST ELECTRODE; MEANS FOR COUPLING SAID FIRST AND SECOND ELECTRODE TO AN ELECTRICAL POWER SUPPLY MEANS; AND MEANS FOR RANDOMLY IMPACTING A FLUID STREAM AGAINST SAID SECOND ELECTRODE FOR VIBRATING SAID SECOND ELECTRODE. 